Laboratory evaluation of the Coulter "three-part electronic differential".

Comparisons were made between "electronic" white blood cell (WBC) differential counts based on nuclear volume, differential counts performed by an automated image analyzer, and conventional manual counts performed by experienced technologists in a routine laboratory setting. The correlation between methods was excellent for lymphocytes (r = 0.9) and granulocytes (r = 0.9), but none of the three methods that were tested produced good results in enumeration of mononuclear cells (r = 0.6). Approximately 85% of the samples on which differentials were requested for an inpatient population could be processed by the electronic counter. Although the electronic counter failed to flag all abnormal samples (there were 6% false negatives), the performance of technologists doing 200 cell differentials was similar. Rapidly generated "electronic differentials" might be a useful and cost-effective adjunct to inpatient hospital practice if certain suggestions were implemented.